Quote: Originally posted by Mixell  | Just one thing, H2O2 is very prone to decomposition, and most of it decomposes in the process.
I made CuCl2 using hydrochloric acid and hydrogen peroxide, I ended up using a nice amount of my 33% hydrogen peroxide (about 2-4 times more than the
stoichiometric amount needed for the reaction). |
I would not recommend a HCl/H2O2 route as this could result in the formation of some Copper oxychloride. If HCl reacts with even dilute H2O2, some
HOCl is formed which could create the unstable Copper hypochlorite. The latter decomposes into Cupric chloride and Copper oxychloride.
Here is my prior post comment on this topic:
Source: http://www.sciencemadness.org/talk/post.php?action=reply&...
| Quote: Originally posted by AJKOER | First, a limited hydrolysis of CuCl2 in water:
CuCl2 + 2 H2O <----> Cu(OH)2 + 2 HCl
But, with the addition of Hydrogen peroxide:
H2O2 + 2 HCl (dilute only) --> 2 HOCl
This reaction is cited by Watt's as one of several preparations for Hypochlorous acid. To quote from "Watts' Dictionary of chemistry", page 16. "—6.
Addition of H2O2 Aq (containing 2.45 p.c. H2O2) to a large excess of Cl Aq produces HClOAq, according to Fairley (B. A. 1874, 57); if much H202 is
added, the HClO Aq is decomposed forming HCl Aq, H20, and evolving O." Link: http://books.google.com/books?pg=PA13&dq=Watt+preparatio...
Next, the reaction of dilute HOCl and Cu(OH)2, forming Copper Oxygen Chloride, a greenish crystalline double salt, CuCl2.Cu(OH)2, which is insoluble
in water.
2 Cu(OH)2 + 4 HOCl --> 2 CuCl2.Cu(OH)2 + 2 H2O + O2
You should also see some oxygen bubbles. The reaction is actual more complex with the intermediate formation of Copper hypochlorite, which decomposes
forming the oxychloride and, per the reference below, actually leaves some CuCl2 in solution.
Reference: "A comprehensive treatise on inorganic and theoretical chemistry", Volume 2, by Joseph William Mellor, page 271. To quote:
"R. Chenevix notes the ready solubility of cupric oxide in chlorine water, and P. Grouvelle found that the soln. obtained by passing chlorine into
water with cupric oxide in suspension possessed bleaching properties, and these were retained even after the soln. had been boiled for a quarter of an
hour. A. J. Balard found that the distillation of P. Grouvelle's liquor furnished some hypochlorous acid and a green oxychloride, 3CuO.CuCl2.4H20, was
formed in the retort. A. J. Balard prepared a soln. of cupric hypochlorite by dissolving cupric hydroxide in hypochlorous acid. It is also made by the
action of cupric sulphate on calcium hypochlorite. A. J. Balard found that copper filings are partially dissolved by hypochlorous acid, the soln.
after standing some time contains cupric chloride, and deposits a green pulverulent cupric oxychloride."
Link:
http://books.google.com/books?pg=PA269&lpg=PA274&dq=...
[Edited on 9-4-2012 by AJKOER] |
[Edited on 25-1-2013 by AJKOER]
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